An important reason to keep Native American languages alive for linguists is that A. These languages may have unusual linguistic features which tells us more about language and cognition
B. There is little linguistic diversity across Native American languages
C. These languages are very similar to Indo-European languages
D. Indigenous communities aren't interested in keeping their language alive, so linguists have to do that work.

I would answer A

Explanation:

A. has the most potential because it talks about unusual linguistics features and it tells us more about the language which is what the fill in sentence above needs because it started off with "An important reason..."

the answer is nurse.

1) technical language (writen technical volcabulary)

2) ordinary langauge

3) literary language (because it's text with a rich, descriptive vocabulary)

4) scientific texts (includes texts such as medical reports, legal texts, academic journals, etc)

5) informational texts (texts that are used to convey information to readers, such as technical guides, costumer guides, textbooks)

6) poetic texts. because they are essays, short stories, poems, etc.